Adventures in Feudal Japan is an oriental/samurai adaptation of the Portable RPG System. The entire Portable RPG System is included in the document, as well as setting information and alternate rules to handle ninja, samurai, and yakuza.

Characters in the system have four Attributes: Strength, Dexterity, Intelligence, and Charisma. Attributes have a numeric value ranging from 1-10, with 4-6 being typical. Players can either randomly generate Ability values using 1d10 or perform a point distribution from a pool of 24 points. Characters then select equipment.